1. Field of the Invention
The present invention relates to a fuel cutoff valve that is attached to an upper portion of a fuel tank and connects and disconnects inside with and from outside of the fuel tank according to the fuel level in the fuel tank.
2. Description of the Related Art
A proposed fuel cutoff valve has a casing with a connection conduit connected to outside of a fuel tank, a cylindrical float valve located in a valve chest in the casing, and a spring supporting the float valve (see JP-A-11-254980). The float valve closes the connection conduit when the fuel level exceeds a preset fluid level. A bottom plate attached to the bottom of the casing is movable in a vertical direction to open and close a connection hole communicating with the valve chest. In the event of an abrupt rise of the fuel level in the fuel tank, for example, by a sudden turn of a vehicle, the fuel level hits against and moves up the bottom plate of the fuel cutoff valve to close the connection hole. This prevents the outflow of the fuel from the fuel tank to a canister.
The structure of the related art fuel cutoff valve, however, does not ensure the smooth up-down motions of the bottom plate in the vertical direction and may not attain a prompt fuel cutoff in the event of an abrupt rise of the fuel level by a sudden turn of the vehicle.